PRIOR APPLICATIONSThis application claims the benefit of the Provisional Application Serial No. 06/124,768, filed on Mar. 7, 1999, the entire contents which are hereby incorporated by reference.[0001]
FIELD OF THE INVENTIONThe present invention relates to the field of angioplasty. In particular, the present invention relates to a coronary cutting, dilating, tamponading and perfusing catheter apparatus which provides dilation of the native lumen while simultaneously making a longitudinal transection of a coronary artery beneath the epicardium that results in a new conduit, all accomplished without blocking blood flow by use of a passive perfusion design apparatus.[0002]
BACKGROUND OF THE INVENTIONIt is well known that any significant reduction or restriction in the flow of blood through the arteries of the body can cause complications which may have serious ischemic consequences. Arterial blockages caused by plaque and fibrotic stenoses in coronary arteries are known to be a leading cause of heart attacks, subsequent strokes, and other debilitating maladies. Accordingly, it is extremely important for the health of a patient that any stenosis, or blockage, which is causing such a condition, be eliminated or reduced.[0003]
With the advent of bypass surgery techniques commonly known as CABG, the ischemic consequences of blockages in arterial segment can be alleviated by grafting around the lesion site a replacement means, typically with a saphenous vein graft. In this manner, blood is allowed to bypass the blockage in the affected artery and the blood supply to the body tissues downstream from the blockage is thereby restored. While bypass surgical procedures have become relatively safe, reliable, and effective, portions of the body must nevertheless be opened to accomplish the surgery. In other words, bypass surgery is invasive, and can consequently require significant post-operative recovery time. To avoid the drawbacks associated with invasive bypass surgery, less invasive surgical procedures have been developed wherein a device is inserted into the bloodstream of a patient and advanced into an artery to reduce or remove an arterial stenosis.[0004]
One well known and frequently used procedure to accomplish this task is popularly known as angioplasty. For a basic angioplasty procedure, a dilating balloon is positioned across the particular stenotic segment and the balloon is inflated to open the artery by breaking up and compressing the plaque which is creating the stenosis. The plaque, however, remains in the artery and is not removed. Unfortunately, in some cases, it appears that the plaque which remains in the artery may still present a stenosis. The removal of intra-arterial deposits are another common method for treating coronary atherosclerosis by mechanical means from a peripheral approach. However, with both of these interventional methods, the six month reoccurrence rate of restenosis can be 40% or more.[0005]
A further alternative treatment method involves percutaneous, intraluminal installation of one or more expandable, tubular stents or prostheses in sclerotic lesions. Stents or prostheses are known in the art as implants which function to maintain patency of a body lumen in humans and especially to such implants for use in blood vessels. They are typically formed from a cylindrical metal mesh which expand when internal pressure is applied. Alternatively, they can be formed of wire wrapped into a cylindrical shape.[0006]
Stents or prostheses can be used in a variety of tubular structures in the body including, but not limited to, arteries and veins, ureters, common bile ducts, and the like. Stents are used to expand a vascular lumen or to maintain its patency after angioplasty or atherectomy procedures, overlie an aortic dissecting aneurysm, tack dissections to the vessel wall, eliminate the risk of occlusion caused by flaps resulting from the intimal tears associated with primary interventional procedure, or prevent elastic recoil of the vessel.[0007]
These metallic stents are deployed inside an arterial segment and embedded in the vessel to maintain patency typically after angioplasty or atherectomy interventions. Once they are so positioned, they are extremely difficult to remove. Often the vessels in which they are placed become occluded or severely restenosed in a relative short period of time. These complications continue to occur the longer the stents remain in place, resulting in total or partial obstruction of blood flow through the artery. Usually, the distal portion of the artery will remain patent and is supplied by collateral circulation through branches of other major arteries. However, the decreased direct blood flow results in many cardiac problems. The use of stents after the interventional procedure or deploying a stent without any adjunctive procedure has decreased this rate to approximately 20% or less in the larger and more proximal arteries which are generally 3.0 mm or more in diameter. Yet, the use of stents have not completely solved the problem of restenosis, where hyperplasia growth sometimes occurs at the terminal ends of the stent. Furthermore, in smaller arteries less than 3.0 mm in diameter, the reoccurrence of a stenosis larger than 50% in relation to the segment diameter can again approximate 40% rate. Long term attrition with stents is not known and as yet there is no method to remove the stents. Brachytherapy and the injection or deposition of various genetic or bioactive materials, including radioactive sources, are currently being explored to decrease the reoccurrence rate. Furthermore, in approximately 30-60% of the vessels treated by angioplasty, there is a re-stenosis. This high recurrence rate is thought to be the result of fibrotic contraction in the lumen of the vessel.[0008]
It has been shown that when an angioplasty procedure is performed after the stenotic segment is longitudinally incised, the opening established through the segment is much larger as compared to standard angioplasty without the prior incisions. Still further, the increase in the opening in the stenotic segment is accomplished without tearing the vessel wall. Moreover, it has been found that incising the stenosis prior to dilation allows greater compression of the stenotic tissue with decreased likelihood of the stenosis rebuilding at a later date. As those skilled in the art will appreciate, the plaque creating a common arterial stenosis is somewhat fibrous and will tend to return to its original pre-dilation configuration. With this fibrous composition, the stenosis is therefore more likely to maintain a compressed configuration if the fibers are incised prior to balloon dilation. On the other hand, if the fibers in the stenosis is not incised first, the completeness of the compression of the stenosis is dependent on whether the inflated balloon is able to break apart fibers in the tissue as those skilled in the art will recognize, dilation of a segment is of course limited by the arteries able to withstand dilation. Over-dilation can have the catastrophic result of rupturing the vessel.[0009]
It is generally agreed that in consequent to the angioplasty procedure, it is the compression of the intra-arterial elements which results in restenosis by causing fibromyoendothelial hyperplasia. The compression which accompanies dilation is intensified by the encircling adventitia. This encasing structure can be stretched only minimally before it ruptures resulting in severe clinical outcomes.[0010]
One of the objects of the present invention and method is to provide a cutting device which, in cooperation with an angioplasty procedure, is able to produce an opening in a stenotic segment where the diameter of the opening is greater than the insertion diameter of the device.[0011]
Another object of the present invention and method is create a longitudinal transection of a coronary artery beneath the epicardium which will result in a new conduit.[0012]
It is also an object of the present invention to provide a device which allows improved control over the length of the incisions produced in the stenotic segment, and the depth of the incisions.[0013]
Yet another object of the present invention is to provide a device which is flexible enough to allow advancement of the device through narrow vessels and around sharp turns.[0014]
Still further, it is an object of the present invention to provide a device for longitudinally incising a stenotic segment of an artery which is relatively easy to manufacture and is comparatively economical.[0015]
Another object of the present invention is to tamponade a longitudinal cut in the arterial wall.[0016]
Still another object of the present invention is to continuously perfuse the distal artery and myocardium until firm clotting has been achieved.[0017]
SUMMARY OF THE INVENTIONIt has been demonstrated in several series of experiments that longitudinal transection of a coronary artery beneath the epicardium will result in a new conduit.[0018]
The treated vessel is then composed of the original arterial wall and another segment of vessel wall which originates on the blood clot and the maturing fibrosis. Such a procedure can be accomplished with minimal interruption of blood flow through the artery.[0019]
If the encircling constraint of the adventitia of the coronary artery is removed the artery can be dilated with minimal pressure to approach a normal diameter. Distal perfusion from the proximal to the distal artery can be supplied through the body of the instrument.[0020]
The present invention and associated method is directed to satisfy the prior defined needs. The device is used for cutting, dilating, tamponading a coronary vessel and has perfusion capabilities. The device consists of instrument having a cylindrical member or capsule surrounded by a dilating and tamponading balloon which in general, resembling a standard catheter assembly. The catheter is designed to be used with a guide wire for positioning the instrument and an advancement catheter permit the proper localization of the instrument inside a coronary artery. There are openings in a proximal cast member to permit the ingress of blood which passes through the body of the instrument. Engaged to the distal end of the tubular member is a distal cast part comprising; 1) an upper portion which contains the advancement catheter, the guide wire, and a transverse strut and 2) a lower partion which contains a chamber containing a deployment balloon, a cutting member.[0021]
In the method of using the incising/dilating/tamponading/perfusing device, the first stage requires the employment of a guide wire that is passed through the area of stenosis in the coronary artery. The instrument is threaded over the guide wire to the stenosis and the distal protuberance performs initial dilation of the stenosis by apply proximal pressure to the advancement catheter. The cutting member is then positioned outside the distal end of the instrument. As the instrument is advanced, the cutting member progressively transects the stenosis and the artery while the rounded distal member progressively dilates the stenosis. With the artery completely incised longitudinally, the adventitia is transected, and the instrument is advanced over the length of the transection. The dilating balloon is distended to further dilate the now pliable artery and to tamponade the site of incision. It remains in this position while distal circulation is supplied by blood passing through the body of the instrument by entering and exiting the openings in the proximal and distal cast parts. Injections of contrast material and slow decompression of the dilating/tamponading balloon indicate when a firm clot has been established.[0022]
These and other features, aspects, and advantages of the present invention will become better understood with regard to the following description, appended claims, and accompanying drawings.[0023]
BRIEF DESCRIPTION OF THE FIGS.FIG. 1. shows the incising/dilating/tamonading/perfusing device of the present invention in a coronary setting.[0024]
FIG. 2. shows a side view of the distal end of the incising/dilating/tamponading/perfusing invention in the disposed with an arterial segment, demonstrating the perfusion holes with both the cutting blade and balloon in a retracted position.[0025]
FIG. 3. shows a side cross-sectional view of the distal end of the incising/dilating/tamponading/perfusing invention, demonstrating the internal lumens with the cutting element in an extended position.[0026]
FIG. 4. shows a cross-sectional view of the distal protuberance of the invention, demonstrating the guide wire and guide wire lumen.[0027]
FIG. 5. shows a cross-sectional view taken from FIG. 2 demonstrating the tamponading balloon, distal member, and associated lumens.[0028]
FIG. 6. shows a cross-sectional view of the distal member demonstrating the upper cast part with advancement catheter, guide wire, and transverse struct and the lower cast part with a chamber embodying the deployment balloon and cutting member.[0029]
FIG. 7. shows a cross-sectional view of the catheter shaft, demonstrating the guide wire and guide wire lumen, balloon inflation/deflation lumen, and the cutting member deployment balloon inflation/deflation lumen.[0030]
FIG. 8. shows a saggital sectional view of the distal member detailing the distal protuberance, the distended deployment balloon, and externally positioned cutting member.[0031]
FIG. 9[0032]a. shows a cross-sectional view of the diseased artery with a guide wire placed in the narrowed lumen.
FIG. 9[0033]b. shows a cross-sectional view of the diseased artery with the incising/dilating/tamponading/perfusing device placed within the target segment demonstrating the initial dilating of the stenosis by the distal protuberance.
FIG. 9[0034]c. shows a cross-sectional view of the diseased artery with the incising/dilating/tamponading/perfusing device placed within the target segment demonstrating the cutting member in an extended position and initial stage of cutting the stenosis.
FIG. 9[0035]d. shows a cross-sectional view of the diseased artery with the incising/dilating/tamponading/perfusing device placed within the target segment demonstrating the perfusion capabilities of the device while further cutting of the stenosis is performed.
FIG. 9[0036]e. shows a cross-sectional view of the diseased artery with the incising/dilating/tamponading/perfusing device placed within the target segment demonstrating the cutting member transacting the adventitial constraint.
FIG. 9[0037]f. shows a cross-sectional view of the diseased artery with the incising/dilating/tamponading device demonstrating further dilation and tamponading of the incised arterial segment.
FIG. 9[0038]g. shows a cross-sectional view of the arterial segment treated with the incising/dilating/tamponading/perfusing device resulting with the artery dilated and the new conduit formed.
DETAILED DESCRIPTION OF THE SPECIFIC EMBODIMENTSFIG. 1. demonstrates the incising/dilating/tamonading/perfusing device of the present invention in a coronary setting using standard techniques for accessing and advancing the invention from a groin incision to the heart.[0039]
Now referring to FIG. 2, the present invention consists of[0040]instrument10 having a cylindrical member orcapsule11 surrounded by a dilating andtamponading balloon12, generally attached to the distal end of atypical advancement catheter22. The catheter of the instrument is constructed of pliable smooth material such as various types of extruded polymeric materials. The cylindrical member, body orcapsule11 is engaged with a proximal37 and distal47 end sections, all of which could be constructed of smooth materials such as sintered steel or plastic. Thecatheter22 is designed to be used with aguide wire20 for positioning the instrument to permit the proper localization of the instrument inside acoronary artery14. The guide wire is common to the industry, while the advancement member may have several configurations which will be flexible but capable of transmitting proximal pressures both continuous and/or intermittent. In addition, the advancement catheter may have a shorted guide wire lumen located at the distal end with a proximal opening to function as a rapid exchange design.Proximal openings16 in theproximal cast member37 permit the ingress of blood which passes through the body of the instrument to flow out ofdistal openings17. The cylindrical body orcapsule11 has other openings or conduits which permit essential parts, such as the advancement catheter, contained guide wire and lumens for expanding the dilatingballoon12 and adeployment balloon26. Theadvancement catheter22 comprises a series of lumens running along the longitudinal length. One lumen in the advancement catheter connects a proximal port todistal catheter port18 permitting theinjection19 of various substances including contrast media and medicaments. As demonstrated in this Figure and as used in clinical practice, theguide wire20 is passed from a peripheral artery proximal through the area of stenosis in the coronary artery. Theadvancement catheter22 and thedistal instrument10 follow the guide wire to the stenosis and thedistal protuberance21 performs initial dilation of the stenosis by apply proximal pressure or a hammering type action to the advancement catheter.
FIG. 3. shows a side or lateral cross-sectional view of the distal end of the incising/dilating/tamponading/perfusing invention, demonstrating the internal lumens and the cutting[0041]element36 in an extended position. Also shown is the distal members construction, withproximal cast part37 havingopenings16 for the perfusion of blood, the central portion consisting of a cylindrical member orcapsule11, and thedistal cast part47 comprising anupper section27 and alower section28, shown in more detail in FIG. 6. The central portion of the cylindrical body II is surrounded with a dilating andtamponading balloon12 which is in fluid communication with a dilating/tamponading lumen23 within theadvancement catheter22. As in theproximal cast part37 of the cylindrical member orcapsule11, the distal cast parts haveopenings17 for the expulsion (perfusion) of blood to the distal artery segment. As shown in the figure, theadvancement catheter22 transcends thecylindrical body11 and terminates into adistal protuberance21. Also extending though theadvancement catheter22 andcylindrical body11 is aguide wire20. As shown in this lateral view of the instrument, the cutting surface has assumed a position outside the distal end of instrument. As the instrument advances the cutting member progressively transects the stenosis and the artery while the rounded distal member progressively dilates the stenosis. With the artery completely incised longitudinally the adventitia has been transected, the instrument is advanced to position the length of the transection and the dilating balloon is distended to further dilate the now pliable artery and to tamponade the site of incision. It remains in this position while distal circulation is supplied by blood passing through the body of the instrument by entering and exiting the openings in the proximal and distal cast parts. Injections of contrast material and slow decompression of the dilating/tamponading balloon indicate when a firm clot has been established. At times a stent may be necessary either initially or later should the area of incision and dilation exceed expectations.
FIG. 4. shows a cross-sectional view taken from FIG. 2. of the distal protuberance of the invention, demonstrating the guide wire and guide wire lumen. The[0042]guide wire lumen24 is positioned relatively in the center of theadvancement catheter22 for theguide wire20 to pass. The position of thedistal protuberance21 functions to initiate the dilation. Theadvancement catheter22 is firmly attached to theprotuberance21.
FIG. 5. shows a cross-sectional view taken from FIG. 2. demonstrating the dilating and tamponading balloon, cylindrical[0043]tubular member11 and associated lumens.
FIG. 6 shows a cross-sectional view taken from FIG. 2. of the distal member demonstrating the[0044]upper cast part27 withadvancement catheter22,guide wire20, separated by a transverse strut34 and thelower cast part28 with achamber29 embodying thedeployment balloon26 and retracted cuttingmember32. The distalupper cast part27 is engaged to theadvancement catheter22 and the transverse strut34. The distallower cast part28 contains achamber29 which embodies thedeployment balloon26, the retracted cuttingmember32, and a conformingshelf30. The upper27 and lower distal cast parts can be joined by appropriate means, e.g. suitable adhesives, after the deployment balloon and cutting member are embodied or can be molded or extruded as a single structure. The transverse strut34 seals the opening in the chamber containing those essential elements and when the two distal cast parts are joined, the transverse strut34 strengthens the apparatus and closes the top of the open chamber which contains a previous place deployment balloon and its associated lumen orconduit25. The top portion of thechamber29 is initially open to permit placement of thedeployment balloon26 and the cuttingmember32, but is closed by the approximation of the upper27 and lower28 cast parts. Thelower cast part28 has acavity29 for the positioning of thedeployment balloon26 and anport38 engaged to its respective inflation/deflation lumen25. Thelower cast part28 also has an opening33 through which the cuttingelement32 protrudes when thedeployment balloon26 is inflated. There is also a mechanism (not shown) which biases the cuttingelement32 in the retracted or contracted position whenever thedeployment balloon26 in deflated. Blood exitsopenings17 are in both the upper27 and lower28 distal cast parts.
FIG. 7. shows a cross-sectional view of the catheter shaft, demonstrating the positioning and relationship of the[0045]guide wire20 andguide wire lumen24, balloon inflation/deflation lumen23, and the deployment balloon inflation/deflation lumen25. Thelumen23 for the dilating/tamponading balloon12, thelumen25 for thedeployment balloon26, and theguide wire lumen24 are created by the use of tubular materials common to the industry. The construction of the catheter can create the lumens by employing a coaxial design or alternately through the use of a multi-lumenal tubular structure. However, it is important that each of this lumens be independent of each other for each lumen functions to perform different and independent operations. Also, each lumen has its own proximal port located on the manifold adapter attached to the proximal end of theadvancement catheter22. Similarly, the dilating andtamponading balloon lumen23 anddeployment balloon lumen25 is in fluid communication with its independent proximal port on the manifold and with the dilating andtamponading balloon12 anddeployment balloon26, respectively.
FIG. 8. shows a saggital sectional view of the distal member detailing the[0046]distal protuberance21, the distendeddeployment balloon26, and externally positioned cuttingmember36. The cutting member32 (retracted) or36 (extended) may have a number of configurations which would include a sharp edged blade, a serrated blade, a cautery, a harmonic scalpel, or a laser. The depth to which the cutting member is important and should be just enough to transect the entire arterial wall, after dilation, including the adventitia. Also shown is theadvancement catheter22 encircled with dilating/tamponating balloon12 and engaged to thedistal protuberance21, both containing aguide wire20. One ormore ports38 are in fluid communication with thedeployment balloon lumen25 in theadvancement catheter22 which functions to inflate and deflate thedeployment balloon26. FIG. 8. also shows thedeployment balloon26 in an inflated and distended configuration, with the externally positioned cuttingmember36 and a conformingshelf30 which seats the balloon.
FIG. 9[0047]a. shows a cross-sectional view of the diseased artery with aguide wire20 placed in the narrowedlumen39. The arterial segment depicted has asignificant stenosis40 surrounded by theadventitia41. As depicted in FIG. 1, the general method of accessing the coronary vasculature is to create a puncture site in the patient's groin area and use one or more guide wires to access the particular coronary artery. Generally, a guiding catheter is employed to facilitate the advancement and placement of the present invention in the selected coronary artery.
FIG. 9[0048]b. shows a cross-sectional view of a diseased arterial segment with the incising/dilating/tamponading/perfusing device placed within the target segment. This figure also demonstrates that the distal protuberance21 (not shown) is used to assist in the initial dilatation such that the present invention can be positioned in thestenosis40.
FIG. 9[0049]c. shows a cross-sectional view of the diseased artery with the incising/dilating/tamponading/perfusing device placed within the target segment and demonstrating the cuttingmember36 in an extended position and initial stage of cutting into thestenosis40. In this stage of the clinical procedure, the cuttingmember36 is extended by inflating thedeployment balloon26 with a fluid. Generally, the fluid used is a contrast medium or a mixed solution of contrast medium and physiologic saline. In this figure, theextended cutting member36 has only penetrated a portion of thestenosis40.
FIG. 9[0050]d. shows a cross-sectional view of the diseased artery with the incising/dilating/tamponading/perfusing device placed within the target segment demonstrating the perfusion capabilities of the device while further cutting of the stenosis is performed. Theextended cutting member36 has begun to transect the adventitia while maintaining perfusion capability.
FIG. 9[0051]e. shows a cross-sectional view of the diseased artery with the incising/dilating/tamponading/perfusion device placed within the target segment demonstrating theextended cutting member36 fully transacting the adventitial constraint. Again, during this stage, perfusion capabilities are maintained.
FIG. 9[0052]f. shows a cross-sectional view of the diseased artery with the incising/dilating/tamponading/perfusion device demonstrating further dilation and tamponading of the incised arterial segment. However, at this stage, thedeployment balloon26 has been deflated by means of withdrawing fluid though thedeployment balloon lumen25 from a proximally positioned port. When the deployment balloon is deflated, theextended cutting member36 is biased such that it becomes retracted into the distallower cast part28 thereby becoming a contracted cuttingmember32.
FIG. 9[0053]g. shows a cross-sectional view of the arterial segment treated with the incising/dilating/tamponading/perfusing device resulting with the artery dilated and the new conduit formed. In the stage of the clinical procedure, the dilating and tamponating balloon has been deflated and the entire distal portion of the present invention is retracted from the treated arterial segment. Shown in this figure is the treatedarterial segment46 which has significantly reduced the stenotic area. The newly formedarterial conduit45 is formed in themyocardium42 as a result of the procedure. Bleeding form the longitudinally incised and dilated artery is contained by the epicardium and the periarterial tissues after the incising/dilating/tamponading balloon is slowly deflated whereby its collapses and can be removed from the treatment site.